Semiconductor pump lasers are used in fiber-optic communication systems, such as optical fiber amplifiers. A pump laser is used to pump a rare earth doped optical fiber amplifier, whereby the pump laser excites the atoms in the optical fiber to a higher energy level. The excited atoms in the optical fiber release energy upon return to a lower energy level, which energy is used to amplify a weak transmission signal. A pump laser is normally sealed in a butterfly package having a pigtail, that is, a short length of optical fiber extending from the pump laser. Ordinarily, a pump laser is permanently connected or wired into an optical fiber amplifier system. In particular, the pump laser electronics are physically soldered to the amplifier circuitry and the pigtail is fusion spliced to the optical fiber amplifier. Fusion splicing entails melting the ends of two fibers together. Splicing results in a permanent connection and generally results in a lower attenuation (loss) of an optical signal.
A pump laser operates continuously to pump the amplifying fiber and, accordingly, is a crucial component of an optical fiber amplifier. With permanent connections of the pump laser in an optical fiber amplifier, such as, the splicing of the optical components and the soldering of the electrical components, a pump laser failure generally requires replacing the optical fiber amplifier or else completely dismantling the failed optical fiber amplifier to access the pump laser. The process of dismantling the failed optical fiber amplifier and replacing the pump laser and then re-assembling the failed optical fiber amplifier in the field can be labor intensive, lengthy, unreliable and expensive. Additionally, spare completely assembled optical fiber amplifiers must be kept in inventory. Consequently, usually for reliability issues, it is much more cost effective to replace the entire failed optical fiber amplifier itself in order to reduce the down time of the optical telecommunication system, rather than to try and dismantle the failed amplifier to replace a pump laser. Alternatively, in the optical amplifier manufacturing process, the failed optical fiber amplifier and its components can be used for scrap parts by the manufacturer.
Another problem associated with the present construction of optical fiber amplifiers relates to the mounting and fusion splicing of the pump laser. For example, if the ends of the pigtail fiber from the pump laser and the amplifying fiber are not aligned properly for fusion splicing, this could amount to an appreciable signal loss. Short of accepting such losses in signal due to any such misalignment, one alternative is to repeat the fusion splicing process to ensure that the pump laser will operate effectively and efficiently.
In light of the foregoing, it is desirable to provide an arrangement where a pump laser can be physically removed with ease from an optical fiber amplifier for servicing, modification, testing, manufacturing and/or replacement. Also, it is desirable to provide a non-permanent way of optically connecting and/or disconnecting, as well as, electrically connecting and/or disconnecting a pump laser from an optical fiber amplifier for servicing, modification, testing, manufacturing and/or replacement. In addition, it is desirable to provide for multiple attempts for optically connecting a pump laser to an optical fiber amplifier. Furthermore, it is desirable to provide an optical fiber amplifier where the various optical and electrical components are separated from the heat generated by a pump laser.